The invention pertains to an electrode structure for a monopolar electrolysis cell for chlor-alkali electrolysis by the diaphragm or membrane cell process with electrodes oriented in essentially the vertical direction with lateral openings; the electrodes, seen in the direction of the vertical axis, being designed as open structures; a flow guide for the recirculating electrolyte being provided in the anodic electrode structure; this guide also serves as the main power feed.
An electrolysis cell for chlor-alkali electrolysis by the diaphragm or membrane process is known from EP-A 383,243, in which the anodes, which extend essentially in the vertical direction, appear as open structures when seen in the direction of the vertical axis. Flow guide elements are provided to promote the upward circulation of anolyte-gas mixture and the downward motion of gas-free anolyte. The main power feed is installed in the interior of the anode, which consists of two parts assembled to form a box-like structure, and is connected by way of current feed plates extending in the form of an X in the radial direction to the anodically active surface of the electrode. The cathode enclosing the anode structure is surrounded in a pocket-like manner by a diaphragm.
It turned out to be a problem with this design that only the cylindrical flow channel in the interior cavity is available for the return of the degassed anolyte. The remaining free cross section of the anode structure is intended for the upward-directed flow of the anolyte-gas mixture. Thus, an unfavorable ratio is obtained between the two cross-sectional areas available for the upward and downward flows.